Current wireless cellular systems are designed to serve user terminals and their applications, in order to allow the continuous streaming of data (e.g., voice and/or video) during a communications session. For these types of applications, when a communications link between a user terminal and a base station is enabled, the communications link is expected to last for a relatively long period of time. Additionally, setting up one or more channels for a communications link between a mobile terminal and a base station may require the mobile terminal and the base station to send and receive various control and signaling data prior to starting a streaming session (e.g. signaling procedures for traffic channel access). Once the communications link is established, other signaling protocols, such as scheduling protocols, may be used to avoid signal interference with other data transmissions. Furthermore, even when a user terminal enters an “idle mode” (i.e., when no data is being transmitted) in order to reduce the amount of signaling that takes place during a communications session, the user terminal may be required to send and receive various control and signaling data prior to entering an “connected mode.” These control and signaling procedures may require a substantial amount of network resources.
A Machine Type Communication (MTC) device is a UE that is used by a machine for a specific application. An example of an MTC device is smart utility meter. Some of these smart meters are located in basements, which suffer from high penetration loss. Therefore, it is difficult for the MTC device to communicate with the network.
In 3GPP, a coverage enhancement is proposed for MTC UEs. The coverage enhancement aims at extending the coverage of an MTC UE, which may be referred to as a CE-MTC UE (Coverage Enhanced MTC UE).
Repetition may be used for a CE-MTC UE. The term repetition level may refer to a number of repetitions for the PRACH. The repetition level allows the MTC UE at different coverage levels to use a different number of repetitions.
The physical random access channel (PRACH) is one of the physical channels that uses coverage enhancement for a CE-MTC UE.